GPR84 antagonists and uses thereof

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63/144,720, filed Feb. 2, 2021; the contents of which are hereby incorporated by reference.

The present invention relates to compounds and methods useful for antagonizing G-protein coupled receptor 84 (GPR84). The invention also provides pharmaceutically acceptable compositions comprising compounds of the present invention and methods of using said compositions in the treatment of various disorders.

The G-protein coupled receptor 84 (GPR84), also known as EX33, GPCR4, and G protein-coupled receptor 84, is a medium chain fatty acid receptor mainly expressed in immune cells and upregulated under inflammatory conditions.

GPR84 was isolated and characterized from human B cells (Wittenberger et al. 2001307, 799-813) as the result of an expressed sequence tag data mining strategy, and also using a degenerate primer reverse transcriptase-polymerase chain reaction (RT-PCR) approach aimed to identify novel chemokine receptors expressed in neutrophils (Yousefi S et al. 200169, 1045-1052). GPR84 remained an orphan GPCR until the identification of medium-chain Free Fatty Acids (FFAs) with carbon chain lengths of 9-14 as ligands for this receptor (Wang J et al. 2006281, 34457-34464). GPR84 was described to be activated by capric acid (C10:0), undecanoic acid (C11:0) and lauric acid (C12:0) with potencies of 5 μM, 9 μM and 11 μM, respectively. Three small molecules were also described to have some GPR84 agonist activity: 3,3′-diindolylmethane (DIM) (Wang et al. 2006), embelin (Hakak Y et al. 2007. WO2007027661 (A2)) and 6-n-octylaminouracil (6-OAU) (Suzuki M et al. 2013288, 10684-10691).

GPR84 has been shown to be expressed in immune cells at least but not limited to polymorphonuclear leukocytes (PMN), neutrophils, monocytes, T cells and B cells. (Hakak et al. 2007; Venkataraman C, Kuo F. 2005101, 144-153; Wang et al. 2006; Yousefi et al. 2001). Higher levels of GPR84 were measured in neutrophils and eosinophils than in T-cells and B-cells. GPR84 expression was demonstrated in tissues that may play a role in the propagation of the inflammatory response such as lung, spleen, bone marrow.

For example, in a recent review, du Bois reported the current status of therapies for lung interstitial diseases, such as idiopathic pulmonary fibrosis (IPF). There are almost 300 distinct injurious or inflammatory causes of interstitial lung disease that can result in diffuse lung scarring, and the initial stages of the IPF pathology are very likely to involve inflammation (du Bois R M. 20109, 129-140), and combination therapies involving anti-inflammatory treatment could be advantageously used.

The expression of GPR84 was highly up-regulated in monocytes/macrophages upon LPS stimulation (Wang et al. 2006).

GPR84 knock-out (KO) mice are viable and indistinguishable from wild-type littermate controls (Venkataraman & Kuo 2005). The proliferation of T and B cells in response to various mitogens is reported to be normal in GPR84-deficient mice (Venkataraman & Kuo 2005). T helper 2 (Th2) differentiated T cells from GPR84 KO mice secreted higher levels of IL4, IL5, IL13, the 3 major Thcytokines, compared to wild-type littermate controls. In contrast, the production of the Th1 cytokine, INFγ, was similar in Th1 differentiated T cells from GPR84 KO mice and wild-type littermate (Venkataraman & Kuo 2005).

In addition, capric acid, undecanoic acid and lauric acid dose dependently increased the secretion of interleukin-12 p40 subunit (IL-12 p40) from RAW264.7 murine macrophage-like cells stimulated with LPS. The pro-inflammatory cytokine IL-12 plays a pivotal role in promoting cell-mediated immunity to eradicate pathogens by inducing and maintaining T helper 1 (Th1) responses and inhibiting T helper 2 (Th2) responses. Medium-chain FFAs, through their direct actions on GPR84, may affect Th1/Th2 balance.

Berry et al. identified a whole-blood 393-gene transcriptional signature for active tuberculosis (TB) (Berry M P R et al. 2010466, 973-977). GPR84 was part of this whole-blood 393-gene transcriptional signature for active TB indicating a potential role for GPR84 in infectious diseases.

GPR84 expression was also described in microglia, the primary immune effector cells of the central nervous system (CNS) of myeloid-monocytic origin (Bouchard C et al. 200755, 790-800). As observed in peripheral immune cells, GPR84 expression in microglia was highly inducible under inflammatory conditions such as TNFα and IL1 treatment but also notably endotoxemia and experimental autoimmune encephalomyelitis (EAE), suggesting a role in neuroinflammatory processes. Those results suggest that GPR84 would be up-regulated in CNS not only during endotoxemia and multiple sclerosis, but also in all neurological conditions in which TNFα or IL-1β pro-inflammatory cytokines are produced, including brain injury, infection, Alzheimer's disease (AD), Parkinson's disease (PD).

GPR84 expression was also observed in adipocytes and shown to be enhanced by inflammatory stimuli (Nagasaki H et al. 2012586, 368-372). The results suggest that the expression of GPR84 is triggered by TNFα from infiltrating macrophages and exacerbates the vicious cycle between adiposity and diabetes/obesity, and therefore the inhibition of GPR84 activity might be beneficial for the treatment of endocrine and/or metabolic diseases.

GPR84 expression is also upregulated in microglia surrounding the neurons, after nerve injury. (Gamo et al, 200828(46), 11980-11988). Furthermore, in GPR84 knock-out mice, hypersensitivity to mechanical stimuli were significantly reduced or completely absent in mouse models of inflammatory and neuropathic pain (Nicol L S C et al. 201535, 8959-8969). Molecules which block the activation of GPR84 may therefore have the potential to deliver broad-spectrum analgesia.

GPR84 expression is increased in human leukemic stem cells (LSC) from acute myeloid leukemia (AML) patients compared to hematopoietic stem cells from healthy donors. GPR84 simultaneously augments β-catenin signaling and an oncogenic transcription program essential for establishment of MLL leukemia (Dietrich et al, 2014124(22), 3284-3294). Suppression of GPR84 significantly inhibited cell growth in pre-LSCs, reduced LSC frequency and impaired reconstitution of stem cell-derived MLL leukemia, which represents a particularly aggressive and drug-resistant subtype of AML. Targeting the oncogenic GPR84/β-catenin signaling axis may represent a novel therapeutic strategy for AML and possibly other leukemias.

GPR84 expression is increased by 49.9 times in M1 type macrophages isolated from aortic atherosclerotic lesions of LDLR−/− mice fed a western diet (Kadl A et al. 2010107, 737-746). Therefore, molecules targeting GPR84 may have a potential benefit in treatment of atherosclerosis.

In experimental esophagitis, GPR84 is upregulated in the esophageal tissue, mainly in the epithelial cells, and is significantly decreased in rats treated with either omeprazole (proton pump inhibitor) or STW5, an herbal preparation shown to ameliorate esophagitis without affecting refluxate pH (Abdel-Aziz H et al. 201521, 1011-1024). This finding is supported by Western blot and immunohistochemistry in rat tissue and HET-1A cells, a human esophageal squamous cell line. GPR84 was also found to be significantly upregulated in esophageal biopsies from patients with grade B reflux esophagitis. Molecules that block the GPR84 receptor activity may therefore represent a new therapeutic paradigm for the treatment of esophagitis.

Therefore, the identification and development of novel compounds, processes for their preparation and their use in the preparation of a medicament would be highly desirable for patients suffering from inflammatory conditions, pain, neuroinflammatory conditions, neurodegenerative conditions, infectious diseases, autoimmune diseases, endocrine and/or metabolic diseases, cardiovascular diseases, leukemia, and/or diseases involving impairment of immune cell functions.

Additionally, the identification and development of novel compounds for use in the preparation of a medicament for the prophylaxis and/or treatment of one or more fibrotic diseases, and more particularly NASH and/or IPF remains highly desirable.

It has now been found that compounds of this invention, and pharmaceutically acceptable compositions thereof, are effective as antagonists of GPR84. In certain embodiments, the invention provides for compounds of the formulae presented herein.

Compounds of the present invention, and pharmaceutically acceptable compositions thereof, are useful for treating a variety of diseases, disorders or conditions, associated with GPR84. Such diseases, disorders, or conditions include those described herein.

Compounds provided by this invention are also useful for the study of GPR84 in biological and pathological phenomena; the study of fibrotic processes occurring in bodily tissues; and the comparative evaluation of new GPR84 inhibitors or other regulators of neutrophil and macrophage chemotaxis in vitro or in vivo.

1. General Description of Certain Embodiments of the Invention:

In certain aspects, the present invention provides a compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein each of Ring A, Ring B, L, L, L, R, R, R, X, m, and n, is as defined below and described in embodiments herein, both singly and in combination.

In some embodiments, the present invention provides a pharmaceutical composition comprising a compound of formula I and a pharmaceutically acceptable carrier, adjuvant, or diluent.

In some embodiments, the present invention provides a method of treating a GPR84-mediated disease, disorder, or condition comprising administering to a patient in need thereof, a compound of formula I, or a pharmaceutically acceptable salt thereof.

2. Compounds and Definitions:

Compounds of the present invention include those described generally herein, and are further illustrated by the classes, subclasses, and species disclosed herein. As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this invention, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75Ed. Additionally, general principles of organic chemistry are described in “Organic Chemistry”, Thomas Sorrell, University Science Books, Sausalito: 1999, and “March's Advanced Organic Chemistry”, 5Ed., Ed.: Smith, M. B. and March, J., John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.

The term “aliphatic” or “aliphatic group”, as used herein, means a straight-chain (i.e., unbranched) or branched, substituted or unsubstituted hydrocarbon chain that is completely saturated or that contains one or more units of unsaturation, or a monocyclic hydrocarbon or bicyclic hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic (also referred to herein as “carbocycle,” “cycloaliphatic” or “cycloalkyl”), that has a single point of attachment to the rest of the molecule. Unless otherwise specified, aliphatic groups contain 1-6 aliphatic carbon atoms. In some embodiments, aliphatic groups contain 1-5 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-4 aliphatic carbon atoms. In still other embodiments, aliphatic groups contain 1-3 aliphatic carbon atoms, and in yet other embodiments, aliphatic groups contain 1-2 aliphatic carbon atoms. In some embodiments, “cycloaliphatic” (or “carbocycle” or “cycloalkyl”) refers to a monocyclic C-Chydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule. Suitable aliphatic groups include, but are not limited to, linear or branched, substituted or unsubstituted alkyl, alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

As used herein, the term “bridged bicyclic” refers to any bicyclic ring system, i.e. carbocyclic or heterocyclic, saturated or partially unsaturated, having at least one bridge. As defined by IUPAC, a “bridge” is an unbranched chain of atoms or an atom or a valence bond connecting two bridgeheads, where a “bridgehead” is any skeletal atom of the ring system which is bonded to three or more skeletal atoms (excluding hydrogen). In some embodiments, a bridged bicyclic group has 7-12 ring members and 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Such bridged bicyclic groups are well known in the art and include those groups set forth below where each group is attached to the rest of the molecule at any substitutable carbon or nitrogen atom. Unless otherwise specified, a bridged bicyclic group is optionally substituted with one or more substituents as set forth for aliphatic groups. Additionally or alternatively, any substitutable nitrogen of a bridged bicyclic group is optionally substituted. Exemplary bridged bicyclics include:

The term “lower alkyl” refers to a Cstraight or branched alkyl group. Exemplary lower alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl.

The term “lower haloalkyl” refers to a Cstraight or branched alkyl group that is substituted with one or more halogen atoms.

The term “heteroatom” means one or more of oxygen, sulfur, nitrogen, phosphorus, or silicon (including, any oxidized form of nitrogen, sulfur, phosphorus, or silicon; the quaternized form of any basic nitrogen or; a substitutable nitrogen of a heterocyclic ring, for example N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl) or NR(as in N-substituted pyrrolidinyl)).

The term “unsaturated,” as used herein, means that a moiety has one or more units of unsaturation.

As used herein, the term “bivalent C(or C) saturated or unsaturated, straight or branched, hydrocarbon chain”, refers to bivalent alkylene, alkenylene, and alkynylene chains that are straight or branched as defined herein.

The term “alkylene” refers to a bivalent alkyl group. An “alkylene chain” is a polymethylene group, i.e., —(CH)—, wherein n is a positive integer, preferably from 1 to 6, from 1 to 4, from 1 to 3, from 1 to 2, or from 2 to 3. A substituted alkylene chain is a polymethylene group in which one or more methylene hydrogen atoms are replaced with a substituent. Suitable substituents include those described below for a substituted aliphatic group.

The term “alkenylene” refers to a bivalent alkenyl group. A substituted alkenylene chain is a polymethylene group containing at least one double bond in which one or more hydrogen atoms are replaced with a substituent. Suitable substituents include those described below for a substituted aliphatic group.

The term “halogen” means F, Cl, Br, or I.

The term “aryl” used alone or as part of a larger moiety as in “aralkyl,” “aralkoxy,” or “aryloxyalkyl,” refers to monocyclic or bicyclic ring systems having a total of five to fourteen ring members, wherein at least one ring in the system is aromatic and wherein each ring in the system contains 3 to 7 ring members. The term “aryl” may be used interchangeably with the term “aryl ring.” In certain embodiments of the present invention, “aryl” refers to an aromatic ring system which includes, but not limited to, phenyl, biphenyl, naphthyl, anthracyl and the like, which may bear one or more substituents. Also included within the scope of the term “aryl,” as it is used herein, is a group in which an aromatic ring is fused to one or more non-aromatic rings, such as indanyl, phthalimidyl, naphthimidyl, phenanthridinyl, or tetrahydronaphthyl, and the like.

The terms “heteroaryl” and “heteroar-,” used alone or as part of a larger moiety, e.g., “heteroaralkyl,” or “heteroaralkoxy,” refer to groups having 5 to 10 ring atoms, preferably 5, 6, or 9 ring atoms; having 6, 10, or 14 π electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. The term “heteroatom” refers to nitrogen, oxygen, or sulfur, and includes any oxidized form of nitrogen or sulfur, and any quaternized form of a basic nitrogen. Heteroaryl groups include, without limitation, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, and pteridinyl. The terms “heteroaryl” and “heteroar-”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where unless otherwise specified, the radical or point of attachment is on the heteroaromatic ring or on one of the rings to which the heteroaromatic ring is fused. Nonlimiting examples include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 4H-quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl, and tetrahydroisoquinolinyl. A heteroaryl group may be mono- or bicyclic. The term “heteroaryl” may be used interchangeably with the terms “heteroaryl ring,” “heteroaryl group,” or “heteroaromatic,” any of which terms include rings that are optionally substituted. The term “heteroaralkyl” refers to an alkyl group substituted by a heteroaryl, wherein the alkyl and heteroaryl portions independently are optionally substituted.

As used herein, the terms “heterocycle,” “heterocyclyl,” “heterocyclic radical,” and “heterocyclic ring” are used interchangeably and refer to a stable 5- to 7-membered monocyclic or 7-10-membered bicyclic heterocyclic moiety that is either saturated or partially unsaturated, and having, in addition to carbon atoms, one or more, preferably one to four, heteroatoms, as defined above. When used in reference to a ring atom of a heterocycle, the term “nitrogen” includes a substituted nitrogen. As an example, in a saturated or partially unsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur or nitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl), orNR (as in N-substituted pyrrolidinyl).

A heterocyclic ring can be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure and any of the ring atoms can be optionally substituted. Examples of such saturated or partially unsaturated heterocyclic radicals include, without limitation, tetrahydrofuranyl, tetrahydrothiophenyl pyrrolidinyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, oxazolidinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl, 2-oxa-6-azaspiro[3.3]heptane, and quinuclidinyl. The terms “heterocycle,” “heterocyclyl,” “heterocyclyl ring,” “heterocyclic group,” “heterocyclic moiety,” and “heterocyclic radical,” are used interchangeably herein, and also include groups in which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or cycloaliphatic rings, such as indolinyl, 3H-indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl. A heterocyclyl group may be mono- or bicyclic. The term “heterocyclylalkyl” refers to an alkyl group substituted by a heterocyclyl, wherein the alkyl and heterocyclyl portions independently are optionally substituted.

As used herein, the term “partially unsaturated” refers to a ring moiety that includes at least one double or triple bond. The term “partially unsaturated” is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aryl or heteroaryl moieties, as herein defined.

As described herein, compounds of the invention may contain “optionally substituted” moieties. In general, the term “substituted,” whether preceded by the term “optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable or chemically feasible compounds. The term “stable,” as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein.

Suitable monovalent substituents on a substitutable carbon atom of an “optionally substituted” group are independently halogen; —(CH)R; —(CH)OR; —O(CH)R, —O—(CH)C(O)OR; —(CH)CH(OR); —(CH2)SR; —(CH)Ph, which may be substituted with R; —(CH)O(CH)Ph which may be substituted with R; —CH═CHPh, which may be substituted with R; —(CH)O(CH)-pyridyl which may be substituted with R; —NO; —CN; —N; —(CH)N(R); —(CH)N(R)C(O)R; —N(R)C(S)R; —(CH)N(R)C(O)NR; —N(R)C(S)NR; —(CH)N(R)C(O)OR; —N(R)N(R)C(O)R; —N(R)N(R)C(O)NR; —N(R)N(R)C(O)OR; —N(R)C(NR)N(R); —(CH)C(O)R; —C(S)R; —(CH)C(O)OR; —(CH)C(O)SR; —(CH)C(O)OSiR; —(CH)OC(O)R; —OC(O)(CH)SR; —SC(S)SR; —(CH)SC(O)R; —(CH)C(O)NR; —C(S)NR; —C(S)SR; —SC(S)SR, —(CH)OC(O)NR; —C(O)N(OR)R; —C(O)C(O)R; —C(O)CHC(O)R; —C(NOR)R; —(CH)SSR; —(CH)S(O)R; —(CH)S(O)OR; —(CH)OS(O)R; —S(O)NR; —(CH)S(O)R; —N(R)S(O)NR; —N(R)S(O)R; —N(OR)R; —C(NH)NR; —P(O)R; —P(O)R; —OP(O)R; —OP(O)(OR); —SiR; —(Cstraight or branched alkylene)O—N(R); or —(Cstraight or branched alkylene)C(O)O—N(R), wherein each Rmay be substituted (e.g., with one, two, or more substituents) as defined below and is independently hydrogen, Caliphatic, —CHPh, —O(CH)Ph, —CH-(5-6 membered heteroaryl ring), or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R, taken together with their intervening atom(s), form a 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below.

Suitable monovalent substituents on R(or the ring formed by taking two independent occurrences of Rtogether with their intervening atoms), are independently halogen, —(CH)R,-(haloR), —(CH)OH, —(CH)OR, —(CH)CH(OR); —O(haloR), —CN, —N, —(CH)-C(O)R, —(CH)C(O)OH, —(CH)C(O)OR, —(CH)SR, —(CH)SH, —(CH)NH, —(CH)NHR, —(CH)NR, —NO, —SiR, —OSiR, —C(O)SR, —(Cstraight or branched alkylene)C(O)OR, or —SSRwherein each Ris unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from Caliphatic, —CHPh, —O(CH)Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of Rinclude ═O and ═S.

Suitable divalent substituents on a saturated carbon atom of an “optionally substituted” group include the following: ═O, ═S, ═NNR*, ═NNHC(O)R*, ═NNHC(O)OR*, ═NNHS(O)R*, ═NR*, ═NOR*, —O(C(R*))O—, or —S(C(R*))S—, wherein each independent occurrence of R* is selected from hydrogen, Caliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an “optionally substituted” group include: —O(CR*)O—, wherein each independent occurrence of R* is selected from hydrogen, Caliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of R* include halogen, —R, -(haloR), —OH, —OR, —O(haloR), —CN, —C(O)OH, —C(O)OR, —NH, —NHR, —NR, or —NO, wherein each Ris unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently Caliphatic, —CHPh, —O(CH)Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on a substitutable nitrogen of an “optionally substituted” group include —R, —NR, —C(O)R, —C(O)OR, —C(O)C(O)R, —C(O)CHC(O)R, —S(O)R, —S(O)NR, —C(S)NR, —C(NH)NR, or —N(R)S(O)R; wherein each Ris independently hydrogen, Caliphatic which may be substituted as defined below, unsubstituted —OPh, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R, taken together with their intervening atom(s) form an unsubstituted 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.